This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-126538, filed Apr. 26, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a single-substrate-heat-processing apparatus for a semiconductor process, which performs processes such as annealing, film formation, etching, oxidation, and diffusion. The term xe2x80x9csemiconductor processxe2x80x9d used herein includes various kinds of processes which are performed to manufacture a semiconductor device or a structure having wiring layers, electrodes, and the like to be connected to a semiconductor device, on a target substrate, such as a semiconductor wafer or an LCD substrate, by forming semiconductor layers, insulating layers, and conductive layers in predetermined patterns on the target substrate.
In the process of manufacturing semiconductor devices, several types of heat-processing apparatuses are used for subjecting target substrates, such as semiconductor wafers, to a semiconductor process, such as annealing, film formation, etching, oxidation, and diffusion. A single-substrate-heat-processing apparatus, which handles wafers one by one, is known as one of these heat-processing apparatuses. The single-substrate-heat-processing apparatus allows a heat process to be relatively easily performed with a high planer uniformity on a wafer, even when the heat process requires the process temperature to be raised and lowered quickly. For this reason, the single-substrate-heat-processing apparatus has become popular, as the size of wafers has been larger, and the size of semiconductor devices has been smaller.
The process conditions, e.g., a process gas, a process temperature, and a process pressure, employed in the single-substrate-heat-processing apparatus largely change depending on the processing steps. For example, when a tantalum oxide film (Ta2O5), which recently attracts attention as a film with good insulating characteristics, is to be formed, heat-processing is performed in deposition, reformation, and crystallization of the film, and different process conditions are respectively employed in these processing steps.
In the manufacture of semiconductor devices, an increase in throughput is an important object in order to increase the mass productivity. As the cost necessary for maintaining the heat-processing apparatus is very high, it is required to reduce the number of units to be installed as small as possible. Under these circumstances, it has been proposed to perform similar processing steps, e.g., reformation and crystallization described above, continuously in a single heat-processing apparatus. Sometimes, however, the two processing steps have largely different process temperatures, like the processing steps of reformation and crystallization do. In this case, it takes time to change, particularly to increase, the temperature of the wafer. This decreases the throughput.
As a single-substrate-heat-processing apparatus, one with a structure that uses a heating lamp disposed under the worktable as a wafer heating source is known. This structure is advantageous in that it can increase the wafer temperature increase speed, while it is disadvantageous in that the window for transmitting light from the lamp therethrough is fogged from inside to likely decrease the heat efficiency and planar uniformity of heating. Therefore, depending on the contents of the process, an apparatus of this type is not appropriate as a mass-production apparatus.
In the most general single-substrate-heat-processing apparatus, a resistance heater disposed in the worktable is used as a wafer heating source. This structure is advantageous in that it can perform stable heating, while it is disadvantageous in that the wafer temperature increase rate decreases. In other words, it takes a comparatively long period of time since the amount of power to be supplied to the resistance heater is increased until the worktable and wafer reach a desired temperature.
It is an object of the present invention to provide a single-substrate-heat-processing apparatus for a semiconductor process, which can perform a plurality of, e.g., two, processes with different process temperatures continuously and quickly.
According to a first aspect of the present invention, there is provided a single-substrate-heat-processing apparatus for a semiconductor process, comprising:
an airtight process chamber;
a worktable configured to place a target substrate thereon and to heat the target substrate in the process chamber;
a first heater configured to heat the worktable;
a gas supply system configured to supply a process gas into the process chamber;
an exhaust system configured to evacuate an interior of the process chamber;
a moving mechanism configured to move the target substrate between a first position on the worktable and a second position above the worktable, the first and second positions being set to subject the target substrate to first and second processes, the first process having a process temperature higher than that of the second process; and
a heat compensation member configured to surround the target substrate so as to compensate for heat dissipated from a peripheral portion of the target substrate when the target substrate is located at the second position, the heat compensation member being disposed in the process chamber and separated from an inner surface of the process chamber through a gap.
According to a second aspect of the present invention, there is provided a single-substrate-heat-processing apparatus for a semiconductor process, comprising:
an airtight process chamber;
a worktable configured to place a target substrate thereon in the process chamber;
a first heater configured to heat the worktable;
a gas supply system configured to supply a process gas into the process chamber;
an exhaust system configured to evacuate an interior of the process chamber;
a first heating zone set in the process chamber in order to subject the target substrate to a first process at a first process temperature, the target substrate being heated, while being placed on the worktable, in the first heating zone by the first heater as a heat source;
a second heating zone set in the process chamber in order to subject the target substrate to a second process at a second process temperature, the target substrate being heated, while being placed above the worktable, in the second heating zone by the first heater as a heat source, the second process temperature being lower than the first process temperature;
a heat compensation member configured to surround the target substrate to compensate for heat dissipated from a peripheral portion of the target substrate in the second heating zone, the heat compensation member being disposed in the process chamber and separated from an inner surface of the process chamber through a gap; and
a moving mechanism configured to move the target substrate between the first and second heating zones.
According to a third aspect of the present invention, there is provided a processing method in a single-substrate-heat-processing apparatus for a semiconductor process, comprising the steps of:
arranging a target substrate at a first position on a worktable disposed in an airtight process chamber and subjecting the target substrate to a first process at a first temperature;
arranging the target substrate at a second position above the worktable before or after the first process and subjecting the target substrate to a second process at a second temperature, the second process temperature being lower than the first process temperature; and
surrounding the target substrate with a heat compensation member during the second process to compensate for heat dissipated from a peripheral portion of the target substrate, the heat compensation member being disposed in the process chamber and separated from an inner surface of the process chamber through a gap.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.